use std::ptr::write_bytes;
use crate::endian_scalar::{emplace_scalar, read_scalar_at};
use crate::primitives::*;
#[derive(Debug)]
pub struct VTableWriter<'a> {
buf: &'a mut [u8],
}
impl<'a> VTableWriter<'a> {
#[inline(always)]
pub fn init(buf: &'a mut [u8]) -> Self {
VTableWriter { buf }
}
#[inline(always)]
pub fn write_vtable_byte_length(&mut self, n: VOffsetT) {
unsafe {
emplace_scalar::<VOffsetT>(&mut self.buf[..SIZE_VOFFSET], n);
}
debug_assert_eq!(n as usize, self.buf.len());
}
#[inline(always)]
pub fn write_object_inline_size(&mut self, n: VOffsetT) {
unsafe {
emplace_scalar::<VOffsetT>(&mut self.buf[SIZE_VOFFSET..2 * SIZE_VOFFSET], n);
}
}
#[inline(always)]
pub fn get_field_offset(&self, vtable_offset: VOffsetT) -> VOffsetT {
let idx = vtable_offset as usize;
unsafe { read_scalar_at::<VOffsetT>(&self.buf, idx) }
}
#[inline(always)]
pub fn write_field_offset(&mut self, vtable_offset: VOffsetT, object_data_offset: VOffsetT) {
let idx = vtable_offset as usize;
unsafe {
emplace_scalar::<VOffsetT>(&mut self.buf[idx..idx + SIZE_VOFFSET], object_data_offset);
}
}
#[inline(always)]
pub fn clear(&mut self) {
let len = self.buf.len();
let p = self.buf.as_mut_ptr() as *mut u8;
unsafe {
write_bytes(p, 0, len);
}
}
}